get_activeGeomLayers: active geom layers

Description

`get_activeGeomLayers` will return the geom layer index which can be active

Usage

get_activeGeomLayers(ggObj)

Value

a numerical vector of indicies (which layer can be interactive)

Arguments

ggObj: a ggplot object

Details

`ggplot2loon` has an argument called `activeGeomLayers`. It is a vector to determine which geom layers can be active. The default setting is `integer(0)`, however, `ggplot2loon` will automatically search the first `geom_histogram` or `geom_point` layer to make it active. `get_activeGeomLayers` is more like a guidance and give us a hint which one can be set as active.

Examples

Run this code

if(interactive()) {
# \donttest{
  df <- data.frame(x = 1:3, y = 1:3, colour = c(1,3,5))
  xgrid <- with(df, seq(min(x), max(x), length = 50))
  interp <- data.frame(
    x = xgrid,
    y = approx(df$x, df$y, xout = xgrid)$y,
    colour = approx(df$x, df$colour, xout = xgrid)$y
  )
  p1 <- ggplot(data = df, aes(x, y, colour = colour)) +
    geom_line(interp, mapping = aes(x, y, colour = colour), size = 2) +
    geom_point(size = 5)
  agL <- get_activeGeomLayers(p1)
  ggplot2loon(p1, activeGeomLayers = agL)

  p2 <- ggplot(economics) +
    geom_rect(
      aes(xmin = start, xmax = end, fill = party),
      ymin = -Inf, ymax = Inf, alpha = 0.2,
      data = presidential
    ) +
    geom_text(
      aes(x = start, y = 2500, label = name),data = presidential,
      size = 3, vjust = 0, hjust = 0, nudge_x = 50
    ) +
    geom_line(aes(date, unemploy)) +
    scale_fill_manual(values = c("blue", "red"))
  # none can be interactive
  agL <- get_activeGeomLayers(p2)
  #transparency is not allowed in tcltk
  ggplot2loon(p2, ggGuides = TRUE, activeGeomLayers = agL)
# }
}